Can the current efficiency be determined from the brine flow rate?
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This post was last edited by sunjl1981 on 2013-1-6 at 22:38. There are currently 4 electrolyzers in use; the operating current for all of them is the same, and the concentration of the brine output from each electrolyzer is also identical. However, the flow rate of the concentrated brine fed into these electrolyzers is about 0.8 m3/h higher for electrolyzers #1 and #2 compared to electrolyzers #3 and #4. Moreover, their cell voltages are basically the same. So, can it be determined that the current efficiency of electrolyzers #1 and #2 is higher than that of electrolyzers #3 and #4 based on the flow rate of the concentrated brine fed into them? Please share your opinions. Thank you! # hcbbs
It makes sense to say that a higher flow rate of brine leads to higher current efficiency, but determining the current efficiency based on the brine flow rate remains a problem – it seems rather impractical. If the original poster can obtain relevant data through experiments, it will undoubtedly point us in a new direction.
The flow rate fluctuates, the flow meter itself has errors, and the current applied also deviates from the set value, either being too high or too low. I don’t think a flow rate difference of 0.8 m3 means much
On the surface, it can be understood this way, after all, the concentration of the lightly salted water remains unchanged, but has the flow rate of that water changed?
If indeed the current and the concentration of the brine exiting the cell are the same, and if there are no issues with the current, the flow meter for the brine entering the cell, or the analysis results, and if all other performance parameters of the electrolyzer remain unchanged, then it means that #1 and #2 have a slightly higher flow rate compared to #3 and #4, while the concentration of the brine exiting these cells is the same. This indicates that #1 and #2 transfer more sodium ions from the anode to the cathode per unit of time. If the concentration at the cathode inlet for all four cells is the same, then the concentration of the alkali exiting #1 and #2 will be higher than that in #3 and #4. With the same flow rate at the cathode, the actual production volume in #1 and #2 will be higher than that in #3 and #4. Using the formula where actual production divided by theoretical production equals current efficiency, and since the current is the same, the theoretical production volume remains unchanged. Therefore, it can be concluded that #1 and #2 have a higher cathode current efficiency than #3 and #4.
From the perspective of advanced control, the original poster’s idea makes sense. In modern electrolysis plants, both the electrolyte materials and the electrolysis equipment can be controlled with high precision. In particular, in recent years, the methods for monitoring electrolyzer parameters have become increasingly advanced and reliable, and there have also been improvements in the technology used for detecting and controlling concentrated and dilute brines. This provides the necessary foundation for optimizing the entire electrolysis process. To implement such a specific solution, it may be necessary to integrate the control system with the monitoring system, control software packages, and optimization parameters in a cohesive manner, and then combine them with the optimization software packages or expert systems provided by the control system suppliers. I believe it is entirely possible to realize the solution envisioned by the original poster. But this requires time and the accumulation of experience; it may not go smoothly in the initial stages. Once this system operates smoothly, it could facilitate production and bring benefits to the factory.
The amount of refined salt water added is an objective indicator of one of the factors affecting current efficiency; however, there are many other factors that influence current efficiency. A change of 0.8 cubic meters is actually very small compared to values in the tens of cubic meters, and such changes are likely to be due to fluctuations. Moreover, they may be masked by differences in tank temperature or variations in the analysis values of the anode solution concentration.